It’s not hard these days to find a property redevelopment programme on TV, whether it’s daytime auctions or primetime with Kirstie and Phil. And if you watch more than an episode or two, it won’t be long before you come across the favoured approach of knocking down a wall to open up a large kitchen-diner. It’s not a new idea, but it’s very much the thing to do these days, it seems, not least because – according to Phil and Kirstie at least – the kitchen is the heart of the modern home.

The equivalent trend in education is the all-through school. It takes a little more thought than knocking down a wall, but this hasn’t stopped around 70 opening up in the past 5 years. Presumably, the thinking is something akin to that with the knocked-through kitchen-diner. Rather than people in separate rooms unable to communicate, we have a free-flow of people, ideas and conversation so that everyone becomes a part of the greater whole, with all the benefits that entails.

Quick read: How failed transitions mean children get 'stuck' in PRUs

Long read: Meet the educational research chief who is in awe of schools

Except, for the most part, it strikes me that the all-through school movement is turning out to be a bit of a missed opportunity. Rather than the beautifully spacious kitchen-diner, we’ve ended up with something more like the old serving hatch of the 1970s. For many all-through schools, the dividing line between primary and secondary has not so much disappeared as had a small peephole poked through.

There are lots of examples of sharing practice. Plenty of schools announce with pride how their secondary PE teachers are used to teach primary pupils. But the very fact that they refer to "secondary teachers" or "primary pupils" reveals the reality of the situation; the same could just as easily have been achieved without the label of "all-through". In fact, the very same is already achieved in many schools nationwide.

Surely the very raison d’être of an all-through school should be to remove all the traditional hurdles of the primary-secondary divide and replace it with something much more cohesive. If your setup means that the daily experience of a Year 6 pupil looks more like that of a Year 4 than a Year 7, then I’d argue the point has been missed. And frankly, if the completion of Year 6 involves any sort of ceremony at all, then can you really describe yourself as an all-through school, any more than taking the door off its hinges turns separate rooms into a kitchen-diner?

It’s only fair to say: I’m biased. As a product and proponent of the three-tier middle school system, I’m always bound to have a view on transition matters. But if all-through is the way we’re going now – and there are more all-through schools than there are middle schools left in England – then surely it ought to be because it’s an improvement on what went before. True, maybe the middle school model has become the equivalent of the hostess trolley (if we can stretch the analogy that far), but we only have to look at the independent sector to see that smoother models are possible.

Good examples exist, of course. Some of the most radical schools have blurred the curriculum and pastoral lines so well that a real sense of cohesion exists from 5 to 16 – or even beyond in some cases. Others will surely follow.

I’ll always mourn the passing of middle schools, not least because they are such joyous places to teach in; I just hope that when something new comes in their stead, it can make the most of what we learned the first time around.

Michael Tidd is headteacher at Medmerry Primary School in West Sussex. He tweets @MichaelT197